Storing frozen biological material, such as plasma, and then thawing it for transfusions is common practice at health care facilities. Typically, bags of plasma or other such materials are frozen to preserve the plasma for subsequent use. For this purpose, plasma is usually stored frozen in a sealed prepackaged pouch or bag.
Before a frozen bag of plasma can be used for a transfusion, the frozen plasma must first be heated to a desired transfusable temperature. Conventionally, a wet bath has been used to warm the frozen plasma. To accomplish the thawing of the frozen plasma, a bag of the frozen plasma is placed directly into a liquid bath which has been preheated to a selected temperature necessary to thaw the frozen plasma. One of the problems with using a wet bath to effect plasma thawing is that contamination of the entire bath will occur if the plasma bag inadvertently leaks during the thawing process. Another problem is that contaminants in the bath may be transferred to the bag of plasma. Consequently, as an alternative to thawing the plasma by direct insertion into a wet bath, an overwrap bag has also been used to protect the bag of biological material and to isolate the bag in case of breakage. The disadvantage of overwrap bags is that they may not always be in convenient access or supply. In addition, the overwrap bags must also be sealed to prevent leakage. Furthermore, the overwrap bags become wet on the outside and must be wiped off with a towel. As a result, the towel and the overwrap bag become a potential breeding ground for bacteria.
As another matter, it is often desirable to thaw biological material rapidly, particularly in emergency situations. Rapid thawing of biological materials limits the amount of time thawed material sits in storage. Thawed plasma has a limited shelf life, and coagulant factors in thawed plasma can degrade in a relatively short period of time. If thawing time is relatively long, medical professionals will often compensate by removing extra frozen units of plasma out of cold storage in advance of an operation, so that a large volume of thawed plasma can be available by the time the operation begins. Of course, this results in wasted plasma if some of the extra units are not needed for the operation or transfusion. Rapid thawing allows medical professionals to have the proper amount of frozen biological materials on an as-needed basis, thereby reducing the potential for wasted materials. Accordingly, an apparatus or method for quickly thawing frozen biological materials in a dry environment is desirable.